Few options were available to the pilot if the flight were to be completed. Weather reports from Tsay Keh described overcast conditions, which would have precluded the pilot from finding a patch of clear air within which to descend, as he had done on approach to Bear Valley. The only aerodrome served by an IFR approach in the area was Mackenzie Airport, 50 miles away. Had there been an IFR approach procedure serving the aerodrome at Tsay Keh (or one of the neighbouring aerodromes), the pilot would have had the option of conducting the flight under IFR. He could have departed Bear Valley in the area of clear weather to the east of the airport, climbed to a minimum en route altitude, and flown to destination where an IFR approach could have been conducted. With no IFR approaches at the north end of Williston Lake and overcast cloud conditions, the pilot's only option for completing the flight was to attempt the flight under VFR. The pilot encountered snowfall that reduced flight visibility to less than that required to maintain visual reference with the ground in an area where the terrain made it necessary to conduct a steep turn to exit the snow conditions. The pilot would have had to remain close to the ice during the turn to regain visual reference; just after rolling out of the turn, the aircraft contacted the ice surface. In conditions of low visibility in snow, and over a frozen, now-covered surface, it would be difficult, if not impossible, to visually acquire the snow surface as it would be indistinguishable from the snow in which the pilot was flying. The descent was made unwittingly, probably because the pilot was concentrating on regaining visual contact with the surface and not flying with reference to the aircraft's altimeter.Analysis Few options were available to the pilot if the flight were to be completed. Weather reports from Tsay Keh described overcast conditions, which would have precluded the pilot from finding a patch of clear air within which to descend, as he had done on approach to Bear Valley. The only aerodrome served by an IFR approach in the area was Mackenzie Airport, 50 miles away. Had there been an IFR approach procedure serving the aerodrome at Tsay Keh (or one of the neighbouring aerodromes), the pilot would have had the option of conducting the flight under IFR. He could have departed Bear Valley in the area of clear weather to the east of the airport, climbed to a minimum en route altitude, and flown to destination where an IFR approach could have been conducted. With no IFR approaches at the north end of Williston Lake and overcast cloud conditions, the pilot's only option for completing the flight was to attempt the flight under VFR. The pilot encountered snowfall that reduced flight visibility to less than that required to maintain visual reference with the ground in an area where the terrain made it necessary to conduct a steep turn to exit the snow conditions. The pilot would have had to remain close to the ice during the turn to regain visual reference; just after rolling out of the turn, the aircraft contacted the ice surface. In conditions of low visibility in snow, and over a frozen, now-covered surface, it would be difficult, if not impossible, to visually acquire the snow surface as it would be indistinguishable from the snow in which the pilot was flying. The descent was made unwittingly, probably because the pilot was concentrating on regaining visual contact with the surface and not flying with reference to the aircraft's altimeter. Weather conditions at the time and location of the occurrence were not suitable for visual flight. While the pilot was attempting to regain visual flight, he allowed the aircraft to descend and it struck the ice surface. The weather and surface conditions were such that it would have been virtually impossible to visually detect the ice surface.Findings as to Causes and Contributing Factors Weather conditions at the time and location of the occurrence were not suitable for visual flight. While the pilot was attempting to regain visual flight, he allowed the aircraft to descend and it struck the ice surface. The weather and surface conditions were such that it would have been virtually impossible to visually detect the ice surface. In the absence of en route weather reporting facilities, the pilot could only estimate weather conditions based on the area forecast and informal reports received from lay personnel.Other Finding In the absence of en route weather reporting facilities, the pilot could only estimate weather conditions based on the area forecast and informal reports received from lay personnel.